Hi Developer Community, I'm experiencing a critical issue with CloudKit schema deployment that's blocking my app release. I've been trying to resolve this for several days and would appreciate any assistance from the community or Apple engineers. Issue Description I'm unable to deploy my CloudKit schema from development to production environment. When attempting to deploy through the CloudKit Dashboard, I either get an "Internal Error" message or the deployment button is disabled. Environment Details App: Reef Trak (Reef aquarium tracking app) CloudKit Container: ************ Development Environment: Schema fully defined and working correctly Production Environment: No schema deployed (confirmed in dashboard) What I've Tried Using the "Deploy Schema to Production" button in CloudKit Dashboard (results in "Internal Error") Exporting schema from development and importing to production (fails) Using CloudKit CLI tools with API token (results in "invalid-scope" errors) Waiting 24-48 hours between attempts in case of propagation delays Current Status App works perfectly in development environment (when run from Xcode) In TestFlight/sideloaded builds (production environment), the app attempts to fetch records but fails with "Did not find record type: Tank" errors Log snippet showing the issue: [2025-03-21] [CloudKit] Schema creation failed: Error saving record <CKRecordID: 0x******; recordName=SchemaSetup_Tank_-**---****, zoneID=_defaultZone:defaultOwner> to server: Cannot create new type Tank in production schema [2025-03-21] [CloudKit] Failed to create schema for Tank after 3 attempts [2025-03-21] [CloudKit] Error creating schema for Tank: Error saving record <CKRecordID: 0x****; recordName=SchemaSetup_Tank_---**-**********, zoneID=_defaultZone:defaultOwner> to server: Cannot create new type Tank in production schema App Architecture & Critical Impact My app "Reef Trak" is built around a core data model where the "Tank" entity serves as the foundational element of the entire application architecture. The Tank entity is not just another data type - it's the primary container that establishes the hierarchical relationship for all other entities: All parameter measurements (pH, temperature, salinity, etc.) are associated with specific tanks All maintenance tasks and schedules are tank-specific All livestock (fish, corals, invertebrates) exist within the context of a tank All user achievements and progress tracking depend on tank-related activities Without the Tank schema being properly deployed to production, users experience what appears to be a completely empty application, despite successful authentication and CloudKit connection. The app shows "Successfully retrieved iCloud data" but displays no content because: The Tank record type doesn't exist in production Without Tanks, all child entities (even if their schemas existed) have no parent to associate with This creates a cascading failure where no data can be displayed or saved This issue effectively renders the entire application non-functional in production, despite working flawlessly in development. Users are left with an empty shell of an app that cannot fulfill its core purpose of reef tank management and monitoring. The inability to deploy the Tank schema to production is therefore not just a minor inconvenience but a complete blocker for the app's release and functionality. Questions Is there an alternative method to deploy schema to production that I'm missing? Could there be an issue with my account permissions or container configuration? Are there known issues with the CloudKit Dashboard deployment functionality? What's the recommended approach when the dashboard deployment fails? I've also submitted a Technical Support Incident, but I'm hoping to get this resolved quickly as it's blocking my App Store release. Thank you for any assistance!

I've been seeing something that I find odd when using two SwiftData models where if I have one model (book, in this case) that has an optional array of another model (page, in this case), the optional array starts out as set to nil, but after about 20 seconds it updates to being an empty array. I see it in Previews and after building. Is this expected behavior? Should I just assume that if there is an optional array in my model it will eventually be initialized to an empty array? Code is below. import SwiftUI import SwiftData @Model final class Book { var title: String = "New Book" @Relationship var pages: [Page]? = nil init(title: String) { self.title = title } } @Model final class Page { var content: String = "Page Content" var book: Book? = nil init() { } } struct ContentView: View { @Environment(\.modelContext) private var modelContext @Query private var books: [Book] var body: some View { NavigationSplitView { List { ForEach(books) { book in NavigationLink { Text("\(book.title)") Text(book.pages?.debugDescription ?? "pages is nil") } label: { Text("\(book.title)") Spacer() Text("\(book.pages?.count.description ?? "pages is nil" )") } } } HStack { Button("Clear Data") { clearData() } Button("Add Book") { addBook() } } .navigationSplitViewColumnWidth(min: 180, ideal: 200) } detail: { Text("Select an item") } } private func clearData() { for book in books { modelContext.delete(book) } try? modelContext.save() } private func addBook() { let newBook = Book(title: "A New Book") modelContext.insert(newBook) } } @main struct BookPageApp: App { var sharedModelContainer: ModelContainer = { let schema = Schema([Book.self, Page.self]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false) do { return try ModelContainer(for: schema, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) } } #Preview { ContentView() .modelContainer(for: Book.self, inMemory: true) }

This simple test fails in my project. Similar code in my application also crashes. How do I debug the problem? What project settings are required. I have added SwiftData as a framework to test (and application) targets? Thanks, The problem is with: modelContext.insert(item) Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) import XCTest import SwiftData @Model class FakeModel { var name: String init(name: String) { self.name = name } } @MainActor final class FakeModelTests: XCTestCase { var modelContext: ModelContext! override func setUp() { super.setUp() do { let container = try ModelContainer(for: FakeModel.self, configurations: ModelConfiguration(isStoredInMemoryOnly: true)) modelContext = container.mainContext } catch { XCTFail("Failed to create ModelContainer: \(error)") modelContext = nil } } func testSaveFetchDeleteFakeItem() { guard let modelContext = modelContext else { XCTFail("ModelContext must be initialized") return } let item = FakeModel(name: "Test") modelContext.insert(item) let fetchDescriptor = FetchDescriptor<FakeModel>() let items = try! modelContext.fetch(fetchDescriptor) XCTAssertEqual(items.count, 1) XCTAssertEqual(items.first?.name, "Test") modelContext.delete(item) let itemsAfterDelete = try! modelContext.fetch(fetchDescriptor) XCTAssertEqual(itemsAfterDelete.count, 0) } }

How do I filter data using @Query with a Set of DateComponents? I successfully saved multiple dates using a MultiDatePicker in AddView.swift. In ListView.swift, I want to retrieve all records for the current or today’s date. There are hundreds of examples using @Query with strings and dates, but I haven’t found an example of @Query using a Set of DateComponents Nothing will compile and after hundreds and hundreds of attempts, my hair is turning gray. Please, please, please help me. For example, if the current date is Tuesday, March 4 205, then I want to retrieve both records. Since both records contain Tuesday, March 4, then retrieve both records. Sorting works fine because the order by clause uses period which is a Double. Unfortunately, my syntax is incorrect and I don’t know the correct predicate syntax for @Query and a Set of DateComponents. Class Planner.swift file import SwiftUI import SwiftData 
 @Model class Planner { //var id: UUID = UUID() var grade: Double = 4.0 var kumi: Double = 4.0 var period: Double = 1.0 var dates: Set<DateComponents> = [] init( grade: Double = 4.0, kumi: Double = 4.0, period: Double = 1.0, dates: Set<DateComponents> = [] ) { self.grade = grade self.kumi = kumi self.period = period self.dates = dates 
 } } @Query Model snippet of code does not work The compile error is to use a Set of DateComponents, not just DateComponents. @Query(filter: #Predicate<Planner> { $0.dates = DateComponents(calendar: Calendar.current, year: 2025, month: 3, day: 4)}, sort: [SortDescriptor(\Planner.period)]) var planner: [Planner] ListView.swift image EditView.swift for record #1 DB Browser for SQLlite: record #1 (March 6, 2025 and March 4, 2025) 
 
 [{"isLeapMonth":false,"year":2025,"day":6,"month":3,"calendar":{"identifier":"gregorian","minimumDaysInFirstWeek":1,"current":1,"locale":{"identifier":"en_JP","current":1},"firstWeekday":1,"timeZone":{"identifier":"Asia\/Tokyo"}},"era":1},{"month":3,"year":2025,"day":4,"isLeapMonth":false,"era":1,"calendar":{"locale":{"identifier":"en_JP","current":1},"timeZone":{"identifier":"Asia\/Tokyo"},"current":1,"identifier":"gregorian","firstWeekday":1,"minimumDaysInFirstWeek":1}}]
 EditView.swift for record #2 DB Browser for SQLlite: record #2 (March 3, 2025 and March 4, 2025) 
 [{"calendar":{"minimumDaysInFirstWeek":1,"locale":{"current":1,"identifier":"en_JP"},"timeZone":{"identifier":"Asia\/Tokyo"},"firstWeekday":1,"current":1,"identifier":"gregorian"},"month":3,"day":3,"isLeapMonth":false,"year":2025,"era":1},{"year":2025,"month":3,"era":1,"day":4,"isLeapMonth":false,"calendar":{"identifier":"gregorian","current":1,"firstWeekday":1,"minimumDaysInFirstWeek":1,"timeZone":{"identifier":"Asia\/Tokyo"},"locale":{"current":1,"identifier":"en_JP"}}}]
 
 Any help is greatly appreciated.

Hello, I'm planning to had an onboarding to one of my apps. I am thinking about a way for a user to not see the onboarding again if he installs the app on another device. So for example, the user completes the onboarding on its iPhone, then downloads the app on its iPad and launch it, he doesn't see the onboarding a second time. I thought about using iCloud NSUbiquitousKeyValueStored to store the onboarding completion state. But I'm not sure when the data is synced to the other device logged into the same Apple account: Immediately even if the app is not installed on the other device (independent from the app, only iCloud thing)? At the same time as the app install on the other device? After the app is first launched on the other device? Of course synchronisation will depend on the Internet connection, speed, etc. so the app should handle the case where the data is not here but what would be the best case scenario? Thank you, Axel

I get this error, i have my own DIKit, and i want to use swiftdata for showing info from persisten model. It works all over the app, but i get this error with my .sheet. // JobCreationView.swift // Features // // Created by Jens Vik on 26/03/2025. // import SwiftUI import DesignKit import DIKit import PresentationKit import CoreKit import DomainKit import SwiftData public struct JobCreationView: View { @Binding var isPresented: Bool // Inject view model using DIKit's property wrapper @Injected((any JobCreationViewModelProtocol).self) private var viewModel // Form state @Injected(ModelContext.self) private var modelContext @State private var date = Date() @State private var isASAP = false @State private var price = "" @State private var jobType = "Fiks" @State private var description = "" // Available job types private let jobTypes = ["Fiks", "Fiksit"] @Query private var userContexts: [UserContextModel] public init(isPresented: Binding<Bool>) { self._isPresented = isPresented print("DEBUG: JobCreationView initialized") } public var body: some View { let city = userContexts.first?.city ?? "Loading..." NavigationView { Form { Section(header: Text("Location")) { Text(city) } Section(header: Text("Details")) { TextField("Price", text: $price) .keyboardType(.numberPad) Picker("Job Type", selection: $jobType) { ForEach(jobTypes, id: \.self) { type in Text(type).tag(type) } } .pickerStyle(SegmentedPickerStyle()) TextEditor(text: $description) .frame(minHeight: 100) .overlay( RoundedRectangle(cornerRadius: 8) .stroke(Color.gray.opacity(0.2), lineWidth: 1) ) } } .navigationBarTitle("Create Job", displayMode: .inline) .navigationBarItems( leading: Button("Cancel") { isPresented = false }, trailing: Button("Post") { // Post functionality will be added later isPresented = false } .disabled( (!isASAP && date < Date()) || price.isEmpty || description.isEmpty) ) } } } How bad is this macro error? error: the replacement path doesn't exist: "/var/folders/dn/x3x4wwkd335_rl91by3tqx5w0000gn/T/swift-generated-sources/@_swiftmacro_10FeatureKit15JobCreationViewV12userContexts33_CDDE5BE156468A2E8CC9B6A7E34B1006LL5QueryfMa.swift" error: the replacement path doesn't exist: "/var/folders/dn/x3x4wwkd335_rl91by3tqx5w0000gn/T/swift-generated-sources/@_swiftmacro_10FeatureKit15JobCreationViewV12userContexts33_CDDE5BE156468A2E8CC9B6A7E34B1006LL5QueryfMa.swift" error: the replacement path doesn't exist: "/var/folders/dn/x3x4wwkd335_rl91by3tqx5w0000gn/T/swift-generated-sources/@_swiftmacro_10FeatureKit15JobCreationViewV12userContexts33_CDDE5BE156468A2E8CC9B6A7E34B1006LL5QueryfMa.swift" error: the replacement path doesn't exist: "/var/folders/dn/x3x4wwkd335_rl91by3tqx5w0000gn/T/swift-generated-sources/@_swiftmacro_10FeatureKit15JobCreationViewV12userContexts33_CDDE5BE156468A2E8CC9B6A7E34B1006LL5QueryfMa.swift" error: the replacement path doesn't exist: "/var/folders/dn/x3x4wwkd335_rl91by3tqx5w0000gn/T/swift-generated-sources/@_swiftmacro_10FeatureKit15JobCreationViewV12userContexts33_CDDE5BE156468A2E8CC9B6A7E34B1006LL5QueryfMa.swift"

LSUB always returns all the subscribed folders. For example lsub "" "test/*" returns a list of all the folders and not just subscribed folders that are subfolders of test. I.e, it returns the same folder list as lsub "" "*". For more details please see https://bugzilla.mozilla.org/show_bug.cgi?id=1817707#c15

iOS 18.2, Swift, Xcode 16.2 I have a Core Data model with two entities - WarehouseArea (of which there is only one object) and StockReeipt (of which there are a couple of hundred thousand). Each StockReceipt must be linked to a WarehouseArea, and a WarehouseArea can be linked to zero, one or many StockReceipts. My problem is that when I create and add one more StockReceipt, the Core Data save takes over 3 seconds to complete. I don't understand why this is so slow. Saving the initial 200,000 StockReceipts only takes 5-6 seconds. When I enable SQL logging I can see that when the WarehouseArea attribute is being set on a StockReceipt, Core Data fetches all of the other StockReceipts (I don't know why) but that only takes 0.2 seconds and none of those StockReceipts are modified, so there shouldn't be any need to process them when saving the context. I have prepared a test project which can be found at https://github.com/DaleReilly/CoreDataSaveTester . Running the project will produce NSLog output showing the times before and after the slow save. Please help me understand what is going on in the background and tell me if there is any way I can speed this up?

In the CloudKit logs I see logs that suggest users getting QUOTA_EXCEEDED error for RecordDelete operations. { "time":"21/07/2025, 7:57:46 UTC" "database":"PRIVATE" "zone":"***" "userId":"***" "operationId":"***" "operationGroupName":"2.3.3(185)" "operationType":"RecordDelete" "platform":"iPhone" "clientOS":"iOS;18.5" "overallStatus":"USER_ERROR" "error":"QUOTA_EXCEEDED" "requestId":"***" "executionTimeMs":"177" "interfaceType":"NATIVE" "recordInsertBytes":54352 "recordInsertCount":40 "returnedRecordTypes":"_pcs_data" } I'm confused as to what this means? Why would a RecordDelete operation have recordInsertBytes? I'd expect a RecordDelete operation to never fail on quotaExceeded and how would I handle that in the app?

I have been trying to find out the app limits to my app when released into the app store, I understand that in the public database the app worldwide can use 200g of bandwidth free per month. What happens after that? is it throttled? is there a pricing structure for overages? thanks

I have an app that uses CKShare to allow users to share CloudKit data with other users. With the first build of the iOS 26, I'm seeing a few issues: I'm not able to add myself as a participant anymore when I have the link to a document. Some participants names no longer show up in the app. Looking at the release notes for iOS & iPadOS 26 Beta, there is a CloudKit section with two bullets: CloudKit sharing URLs do not launch third-party apps. (151778655) The request access APIs, such as CKShareRequestAccessOperation, are available in the SDK but are currently nonfunctional. (151878020) It sounds like the first issue is addressed by the first bullet, although the error message makes me wonder if I need to make changes to my iCloud account permissions or something in order to open it. It works fine in iOS 18.5. This is the error I get when I try to open a link to a shared document (I blocked out my email address, which is what was in quotes): As far as the second issue, I am really confused about what is going on. Some names still show up, while others do not. I can't find a pattern, and the missing users are not on the iOS 26 beta. The release notes mention CKShareRequestAccessOperation being nonfunctional, which is new in the beta and has some minor documentation, but I can't find information about how it's supposed to be used yet. In previous years there have been WWDC sessions about what's new in CloudKit, but I haven't found anything that talks about these changes to document sharing. Is there a guide or session somewhere that I'm missing? Does anyone know what's going on with these changes to CloudKit?

What is the best way to switch between Core Data Persistent Stores? My use case is that I have a multi-user app that stores thousands of data items unique to each user. To me, having Persistent Stores for each user seems like the best design to keep their data separate and private. (If anyone believes that storing the data for all users in one Persistent Store is a better design, I'd appreciate hearing from them.) Customers might switch users 5 to 10 times a day. Switching users must be fast, say a second or two at most.

I am trying to extend my PersistedModels like so: @Versioned(3) @Model class MyType { var name: String init() { name = "hello" } } but it seems that SwiftData's@Model macro is unable to read the properties added by my @Versioned macro. I have tried changing the order and it ignores them regardless. version is not added to schemaMetadata and version needs to be persisted. I was planning on using this approach to add multiple capabilities to my model types. Is this possible to do with macros? VersionedMacro /// A macro that automatically implements VersionedModel protocol public struct VersionedMacro: MemberMacro, ExtensionMacro { // Member macro to add the stored property directly to the type public static func expansion( of node: AttributeSyntax, providingMembersOf declaration: some DeclGroupSyntax, in context: some MacroExpansionContext ) throws -> [DeclSyntax] { guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self), let firstArgument = argumentList.first?.expression else { throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)") } let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces) // Add the stored property with the version value return [ "public private(set) var version: Int = \(raw: versionValue)" ] } // Extension macro to add static property public static func expansion( of node: SwiftSyntax.AttributeSyntax, attachedTo declaration: some SwiftSyntax.DeclGroupSyntax, providingExtensionsOf type: some SwiftSyntax.TypeSyntaxProtocol, conformingTo protocols: [SwiftSyntax.TypeSyntax], in context: some SwiftSyntaxMacros.MacroExpansionContext ) throws -> [SwiftSyntax.ExtensionDeclSyntax] { guard let argumentList = node.arguments?.as(LabeledExprListSyntax.self), let firstArgument = argumentList.first?.expression else { throw MacroExpansionErrorMessage("@Versioned requires a version number, e.g. @Versioned(3)") } let versionValue = firstArgument.description.trimmingCharacters(in: .whitespaces) // We need to explicitly add the conformance in the extension let ext = try ExtensionDeclSyntax("extension \(type): VersionedModel {}") .with(\.memberBlock.members, MemberBlockItemListSyntax { MemberBlockItemSyntax(decl: DeclSyntax( "public static var version: Int { \(raw: versionValue) }" )) }) return [ext] } } VersionedModel public protocol VersionedModel: PersistentModel { /// The version of this particular instance var version: Int { get } /// The type's current version static var version: Int { get } } Macro Expansion:

Hey all, This is my first app with Swift, and first app using CloudKit / iCloud - although I have launched other iOS app successfully. When I created the app, I selected "none" for storage my bundle identifier looks like this: io.mysite.appname I have the iCloud capability added, with CloudKit checked, and the container also checked that looks like this: iCloud.io.mysite.appname Push Notificaitons capability is also added, but there is no configuration. I have tried automatically managed signing, as well as a manually created provisioning profile.. Every time I build the app onto my device - when I check it out in settings, icloud is not listed. When I go through iCloud into icloud drive, the app is also not listed. I have cleaned the build many times, deleted and reinstalled the app on my phone many times. I am definitely logged into iCloud etc. Obviously I have spent plenty of times trying to debug with various LLMs, but we all seem to be at a loss for what I'm missing or doing wrong. Would love any tips or pointers I may be missing, thank you!

I'm trying to convert some data, then save it back to Core Data. Sometimes this works fine without an issue, but occasionally I'll get an error Thread 1: EXC_BAD_ACCESS (code=1, address=0x0) It seems to occur when saving the core data context. I'm having trouble trying to debug it as it doesn't happen on the same object each time and can't reliably recreate the error Full view code can be found https://pastebin.com/d974V5Si but main functions below var body: some View { VStack { // Visual code here } .onAppear() { DispatchQueue.global(qos: .background).async { while (getHowManyProjectsToUpdate() > 0) { leftToUpdate = getHowManyProjectsToUpdate() updateLocal() } if getHowManyProjectsToUpdate() == 0 { while (getNumberOfFilesInDocumentsDirectory() > 0) { deleteImagesFromDocumentsDirectory() } if getNumberOfFilesInDocumentsDirectory() == 0 { DispatchQueue.main.asyncAfter(deadline: .now()) { withAnimation { self.isActive = true } } } } } } } update local function func updateLocal() { autoreleasepool { let fetchRequest: NSFetchRequest<Project> = Project.fetchRequest() fetchRequest.predicate = NSPredicate(format: "converted = %d", false) fetchRequest.fetchLimit = 1 fetchRequest.sortDescriptors = [NSSortDescriptor(keyPath: \Project.name, ascending: true), NSSortDescriptor(keyPath: \Project.name, ascending: true)] do { let projects = try viewContext.fetch(fetchRequest) for project in projects { currentPicNumber = 0 currentProjectName = project.name ?? "Error loading project" if let projectMain = project.mainPicture { currentProjectImage = getUIImage(picture: projectMain) } if let pictures = project.pictures { projectPicNumber = pictures.count // Get main image if let projectMain = project.mainPicture { if let imgThumbData = convertImageThumb(picture: projectMain) { project.mainPictureData = imgThumbData } } while (getTotalImagesToConvertForProject(project: project ) > 0) { convertImageBatch(project: project) } project.converted = true saveContext() viewContext.refreshAllObjects() } } } catch { print("Fetch Failed") } } } convertImageBatch function func convertImageBatch(project: Project) { autoreleasepool { let fetchRequestPic: NSFetchRequest<Picture> = Picture.fetchRequest() let projectPredicate = NSPredicate(format: "project = %@", project) let dataPredicate = NSPredicate(format: "pictureData == NULL") fetchRequestPic.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [projectPredicate, dataPredicate]) fetchRequestPic.fetchLimit = 5 fetchRequestPic.sortDescriptors = [NSSortDescriptor(keyPath: \Picture.dateTaken, ascending: true)] do { let pictures = try viewContext.fetch(fetchRequestPic) for picture in pictures { currentPicNumber = currentPicNumber + 1 if let imgData = convertImage(picture: picture), let imgThumbData = convertImageThumb(picture: picture) { // Save Converted picture.pictureData = imgData picture.pictureThumbnailData = imgThumbData // Save Image saveContext() viewContext.refreshAllObjects() } else { viewContext.delete(picture) saveContext() viewContext.refreshAllObjects() } } } catch { print("Fetch Failed") } } } And finally saving func saveContext() { do { try viewContext.save() } catch { let nsError = error as NSError fatalError("Unresolved error \(nsError), \(nsError.userInfo)") } }

If I set my build settings "default actor isolation" to MainActor, how do my @ModelActor actors and model classes need to look like ? For now, I am creating instances of my @ModelActor actors and passing my modelContext container and processing all data there. Everything stays in this context. No models are transferred back to MainActor. Now, after changing my project settings, I am getting a huge amount of warnings. Do I need to set all my model classes to non-isolated and the @ModelActor actor as well? Is there any new sample code to cover this topic ... did not find anything for now. Thanks in advance, Marc

When a user first downloads my application they are prompted to sign into their apple account via a pop up. I have not had this pop up previously, I believe the change occurred after iOS18. I have functions that do a few things: Retrieves userRecordID Retrieves a userprofile(via userrecordid) from cloudkit.

Does the CloudKit participant limit of 100 include the owner?

I have an app that uses NSPersistentCloudKitContainer stored in a shared location via App Groups so my widget can fetch data to display. It works. But if you reset your iPhone and restore it from a backup, an error occurs: The file "Name.sqlite" couldn't be opened. I suspect this happens because the widget is created before the app's data is restored. Restarting the iPhone is the only way to fix it though, opening the app and reloading timelines does not. Anything I can do to fix that to not require turning it off and on again?

I’m getting a 0xdead10cc crash in a basic CoreData/CloudKit application. I only have one CoreData save call and its made when the app is in the foreground and it's minor so I don't think its being caused by that. My best guess is that it's related to background syncing of CloudKit. Does anyone know how to fix it? I've been advised that adding the following code around any saves will fix it, but it seems weird that this is the solution. I would expect the inner CoreData/CloudKit engine to handle this. ProcessInfo().performActivity(reason: "Persisting to context") { // Save to context here } Here is the crashing thread Thread 7: 0 libsystem_kernel.dylib 0x00000001edc086f4 guarded_pwrite_np + 8 (:-1) 1 libsqlite3.dylib 0x00000001ca71b6e4 seekAndWrite + 456 (sqlite3.c:44287) 2 libsqlite3.dylib 0x00000001ca6d5df4 unixWrite + 180 (sqlite3.c:44365) 3 libsqlite3.dylib 0x00000001ca723b90 pagerWalFrames + 872 (sqlite3.c:67093) 4 libsqlite3.dylib 0x00000001ca6d5b14 sqlite3PagerCommitPhaseOne + 316 (sqlite3.c:70409) 5 libsqlite3.dylib 0x00000001ca6c6494 sqlite3BtreeCommitPhaseOne + 172 (sqlite3.c:81106) 6 libsqlite3.dylib 0x00000001ca6c605c vdbeCommit + 1136 (sqlite3.c:94124) 7 libsqlite3.dylib 0x00000001ca69f778 sqlite3VdbeHalt + 1340 (sqlite3.c:94534) 8 libsqlite3.dylib 0x00000001ca6c0618 sqlite3VdbeExec + 42648 (sqlite3.c:103922) 9 libsqlite3.dylib 0x00000001ca6b56c0 sqlite3_step + 960 (sqlite3.c:97886) 10 CoreData 0x00000001a459ab38 _execute + 128 (NSSQLiteConnection.m:4614) 11 CoreData 0x00000001a45fe004 -[NSSQLiteConnection commitTransaction] + 728 (NSSQLiteConnection.m:3278) 12 CoreData 0x00000001a469888c _executeGenerateObjectIDRequest + 388 (NSSQLCore_Functions.m:6021) 13 CoreData 0x00000001a46986a4 -[NSSQLGenerateObjectIDRequestContext executeRequestCore:] + 28 (NSSQLObjectIDRequestContext.m:42) 14 CoreData 0x00000001a45fb380 -[NSSQLStoreRequestContext executeRequestUsingConnection:] + 240 (NSSQLStoreRequestContext.m:183) 15 CoreData 0x00000001a45fb0a8 __52-[NSSQLDefaultConnectionManager handleStoreRequest:]_block_invoke + 60 (NSSQLConnectionManager.m:307) 16 CoreData 0x00000001a45fafe0 __37-[NSSQLiteConnection performAndWait:]_block_invoke + 48 (NSSQLiteConnection.m:755) 17 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 18 libdispatch.dylib 0x00000001a43677fc _dispatch_lane_barrier_sync_invoke_and_complete + 56 (queue.c:1104) 19 CoreData 0x00000001a45b5ba4 -[NSSQLiteConnection performAndWait:] + 176 (NSSQLiteConnection.m:752) 20 CoreData 0x00000001a45b5a68 -[NSSQLDefaultConnectionManager handleStoreRequest:] + 248 (NSSQLConnectionManager.m:302) 21 CoreData 0x00000001a45b5938 -[NSSQLCoreDispatchManager routeStoreRequest:] + 228 (NSSQLCoreDispatchManager.m:60) 22 CoreData 0x00000001a45b573c -[NSSQLCore dispatchRequest:withRetries:] + 172 (NSSQLCore.m:4044) 23 CoreData 0x00000001a46737b4 -[NSSQLCore _obtainPermanentIDsForObjects:withNotification:error:] + 1324 (NSSQLCore.m:2830) 24 CoreData 0x00000001a460ba98 -[NSSQLCore _prepareForExecuteRequest:withContext:error:] + 272 (NSSQLCore.m:2946) 25 CoreData 0x00000001a460a0f8 __65-[NSPersistentStoreCoordinator executeRequest:withContext:error:]_block_invoke.547 + 8988 (NSPersistentStoreCoordinator.m:2995) 26 CoreData 0x00000001a45d6660 -[NSPersistentStoreCoordinator _routeHeavyweightBlock:] + 264 (NSPersistentStoreCoordinator.m:668) 27 CoreData 0x00000001a45ded28 -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 1200 (NSPersistentStoreCoordinator.m:2810) 28 CoreData 0x00000001a4655988 -[NSManagedObjectContext save:] + 984 (NSManagedObjectContext.m:1593) 29 CoreData 0x00000001a46f47dc __52+[NSCKEvent beginEventForRequest:withMonitor:error:]_block_invoke_2 + 352 (NSCKEvent.m:76) 30 CoreData 0x00000001a45c28f0 developerSubmittedBlockToNSManagedObjectContextPerform + 476 (NSManagedObjectContext.m:3984) 31 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 32 libdispatch.dylib 0x00000001a43677fc _dispatch_lane_barrier_sync_invoke_and_complete + 56 (queue.c:1104) 33 CoreData 0x00000001a4615c34 -[NSManagedObjectContext performBlockAndWait:] + 308 (NSManagedObjectContext.m:4108) 34 CoreData 0x00000001a46f45ac __52+[NSCKEvent beginEventForRequest:withMonitor:error:]_block_invoke + 192 (NSCKEvent.m:66) 35 CoreData 0x00000001a4825e68 -[PFCloudKitStoreMonitor performBlock:] + 92 (PFCloudKitStoreMonitor.m:148) 36 CoreData 0x00000001a46f4394 +[NSCKEvent beginEventForRequest:withMonitor:error:] + 256 (NSCKEvent.m:61) 37 CoreData 0x00000001a47cc6ec __57-[NSCloudKitMirroringDelegate _performExportWithRequest:]_block_invoke + 260 (NSCloudKitMirroringDelegate.m:1433) 38 CoreData 0x00000001a47c9970 __92-[NSCloudKitMirroringDelegate _openTransactionWithLabel:assertionLabel:andExecuteWorkBlock:]_block_invoke + 72 (NSCloudKitMirroringDelegate.m:957) 39 libdispatch.dylib 0x00000001a4356248 _dispatch_call_block_and_release + 32 (init.c:1549) 40 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 41 libdispatch.dylib 0x00000001a435f5cc _dispatch_lane_serial_drain + 768 (queue.c:3934) 42 libdispatch.dylib 0x00000001a4360158 _dispatch_lane_invoke + 432 (queue.c:4025) 43 libdispatch.dylib 0x00000001a436b38c _dispatch_root_queue_drain_deferred_wlh + 288 (queue.c:7193) 44 libdispatch.dylib 0x00000001a436abd8 _dispatch_workloop_worker_thread + 540 (queue.c:6787) 45 libsystem_pthread.dylib 0x0000000227213680 _pthread_wqthread + 288 (pthread.c:2696) 46 libsystem_pthread.dylib 0x0000000227211474 start_wqthread + 8 (:-1)